1. Field of the Invention
The present invention relates to a flyback transformer, and more particularly, to a flyback transformer having a flexible coil winding structure in a planar shape and a manufacturing process thereof.
2. Description of the Prior Art
Generally, a flyback transformer (hereinafter, referred to as "FBT") is employed as a device for generating high voltage in TV receivers, oscilloscopes and CRTs, etc. This FBT basically includes a primary coil winding and a secondary coil winding, which are electromagnetically interconnected by a magnetizable core. The value of the generated voltage depends on the ratio of the number of turns of the secondary winding to that of the primary winding. In case of the conventional FBT for generating higher voltages, a greater number of turns of the secondary winding has been required, which has resulted in an increase in the volume thereof, and consequently lead to poor efficiency and also poor high voltage regulation.
To solve the above problems, U.S. Pat. No. 5,392,020 issued on Feb. 21, 1995 to Kern K. N. Chang describes a flexible transformer apparatus as illustrated in FIGS. 1A to 1D, which will be explained below.
FIG. 1A is a perspective view schematically illustrating the configuration of the flexible transformer apparatus. As illustrated in the figure, the flexible transformer apparatus includes a pair of planar sheets 10, 20 and a magnetizable sheet 30 interposed between them. The planar sheets 10, 20 consist of respectively an insulator sheet and a plurality of conductor lines 12, 14 and 22, 24 vapor-deposited thereon. The conductor lines 12, 14 and 22, 24 are connected with each other in a zigzag formation to form a secondary coil winding.
FIGS. 1B and 1C are plan views illustrating the planar sheets 10, 20 of FIG. 1A. As shown in the figures, the first planar sheet 10 and the second planar sheet 20 include the parallel conductor lines 12, 14 and 22, 24 respectively. The parallel conductor lines 12, 24 and 22, 24 are inclined at a predetermined angle and arranged at longitudinally interspaced distances. These configured parallel conductor lines are interconnected so as to form the flexible transformer apparatus, as illustrated in FIG. 1A.
The parallel conductive lines 12, 14 and 22, 24 may be formed on the surface of the insulator sheet by conventional vapor deposition techniques, RF sputtering techniques, etc., using photolithographic procedures. The materials used for the conductor lines are noble metals such as platinum, gold, silver, copper, aluminum and their alloys.
FIG. 1D is a transverse sectional view of the flexible transformer apparatus of FIG. 1A, which illustrates the electrically connected configuration of the conductor lines 12, 14 and 22, 24 on the planar sheets 10, 20. With regard to the electrical connection of the conductor lines, the patent describes as follows: Each of the conductor lines is provided with apertures 12a, 12b, 14a, 14b and 22a, 22b, 24a, 24b formed at both ends thereof, and connecting rods 40 are inserted into the apertures to thereby provide the electrical connection between the conductor lines of the first planar sheet and those of the second one.
In the above-described flexible transformer apparatus, however, it is understood that the secondary windings require about 4,000 turns of coil winding, and the conductor lines have a width of from 40 to 125 microns. Therefore, it is not possible actually to form the apertures at both ends of those very fine conductor lines, and also insert mechanically the connecting rod into these fine apertures one by one for achieving the electrical connection between the conductor lines. Furthermore, this mechanical connection practice is not adaptable for substantial production, especially mass production of the above flexible transformer apparatus.